U.S. patent application number 12/382597 was filed with the patent office on 2009-08-06 for connector for a respiratory mask and a respiratory mask.
This patent application is currently assigned to ResMed Limited. Invention is credited to Geoffrey Crumblin, Joanne E. Drew, Michael K. Gunaratnam, Phillip Jenkinson, Susan R. Lynch.
Application Number | 20090194112 12/382597 |
Document ID | / |
Family ID | 3815221 |
Filed Date | 2009-08-06 |
United States Patent
Application |
20090194112 |
Kind Code |
A1 |
Gunaratnam; Michael K. ; et
al. |
August 6, 2009 |
Connector for a respiratory mask and a respiratory mask
Abstract
A connector includes a mask end for connecting with the interior
of a respiratory mask, a supply conduit end, and a gas washout vent
passage having an inlet adjacent to, or forming part of, the mask
end in fluid communication with the interior of the respiratory
mask and an outlet in fluid communication with atmosphere. The vent
outlet of the vent passage is disposed on the side of the connector
remote from the mask end. A respiratory mask includes a mask shell,
a mask inlet for connecting with the outlet of a breathable gas
supply conduit, and a gas washout vent passage. A vent outlet is
disposed on the side of the mask remote from the mask interior and
is adapted to direct the washout gas in a direction substantially
parallel to the longitudinal axis of the mask inlet and away from
the mask inlet.
Inventors: |
Gunaratnam; Michael K.;
(Marsfield, AU) ; Drew; Joanne E.; (Balgowlah
Heights, AU) ; Crumblin; Geoffrey; (Baulkham Hills,
AU) ; Jenkinson; Phillip; (Chittaway Point, AU)
; Lynch; Susan R.; (Bella Vista, AU) |
Correspondence
Address: |
NIXON & VANDERHYE, PC
901 NORTH GLEBE ROAD, 11TH FLOOR
ARLINGTON
VA
22203
US
|
Assignee: |
ResMed Limited
Bella Vista
AU
|
Family ID: |
3815221 |
Appl. No.: |
12/382597 |
Filed: |
March 19, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11362722 |
Feb 28, 2006 |
7523753 |
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12382597 |
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10636588 |
Aug 8, 2003 |
7066178 |
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11362722 |
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09594775 |
Jun 16, 2000 |
6691707 |
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10636588 |
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Current U.S.
Class: |
128/206.21 |
Current CPC
Class: |
A61M 16/0683 20130101;
A61M 16/0825 20140204; A61M 16/0666 20130101; A61M 16/0633
20140204; A61M 16/0616 20140204; A61M 16/0622 20140204; A61M
2202/0225 20130101; A61M 16/0875 20130101; A61M 2206/14 20130101;
A61M 16/06 20130101; A61M 2205/42 20130101; A61M 16/0066 20130101;
A61M 16/0816 20130101; A61M 16/08 20130101; A61M 16/0638 20140204;
A61M 2202/0225 20130101; A61M 2202/0085 20130101 |
Class at
Publication: |
128/206.21 |
International
Class: |
A61M 16/06 20060101
A61M016/06 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 18, 1999 |
AU |
PQ 1029 |
Claims
1. A connector comprising: a mask end for connecting in fluid
communication with the interior of a respiratory mask; a supply
conduit end disposed at an angle to the mask end for connecting in
fluid communication with the outlet of a breathable gas supply
conduit; and a gas washout vent passage having an inlet adjacent
to, or forming part of, the mask end in fluid communication with
the interior of the respiratory mask and an outlet in fluid
communication with the atmosphere, the outlet including an interior
surface that forms a smooth prolongation with an adjacent exterior
surface of the connector, the vent outlet is disposed on the side
of the connector remote the mask end, has a generally part-annular
cross-section and is adapted to direct the washout gas in a
direction substantially perpendicular to the longitudinal axis of
the mask end and substantially perpendicular to the longitudinal
axis of the mask end and substantially parallel to the longitudinal
axis of the supply conduit end towards the supply conduit end.
2. The connector as claimed in claim 1, wherein the supply conduit
end is substantially perpendicular to the mask end.
3. The connector as claimed in claim 1, wherein the supply conduit
end is angled at approximately 135 degrees to the mask end.
4. The connector as claimed in claim 1, wherein the connector
includes a body portion and a cap portion, said body portion
including said interior surface.
5. The connector as claimed in claim 4, wherein the cap portion
includes an interior surface spaced apart from the body portion
interior surface, said body portion interior surface and said cap
portion interior surface defining said vent passage
therebetween.
6. The connector as claimed in claim 4, wherein the cap portion is
detachable from the body portion.
7. The connector as claimed in claim 4, wherein the cap portion and
body portion are rigid and fixed relative to each other when
attached.
8. The connector as claimed in claim 4, wherein the exterior of the
body portion includes grooves or ridges adapted to engage ridges or
grooves respectively on the interior of the cap portion to attach
the cap portion to the body portion.
9. The connector as claimed in claim 4, wherein one of the body
portion and the cap portion includes a spacer extending between
said cap portion interior surface and said body portion exterior
surface.
10. The connector as claimed in claim 4, wherein the vent passage
inlet is formed in the body portion adjacent to, and downstream of,
the mask end relative to the washout gas flow and is in fluid
communication with the mask interior via the body portion.
11-23. (canceled)
24. A respiratory mask comprising: a mask shell defining an
interior of the respiratory mask; a mask inlet for connecting in
fluid communication with the outlet of a breathable gas supply
conduit; and a gas washout vent passage having an inlet forming
part of the mask shell and in fluid communication with the interior
of the respiratory mask and an outlet in fluid communication with
atmosphere, the outlet including an interior surface that forms a
smooth prolongation with an adjacent exterior surface of the mask
shell, the vent outlet is disposed on the side of the mask remote
the mask interior and is adapted to direct the washout gas in a
direction substantially parallel to the longitudinal axis of the
mask inlet and away from the mask inlet.
25. The mask as claimed in claim 24, wherein the mask shell
includes a body portion and a cap portion, said body portion
including said interior surface.
26. The mask as claimed in claim 25, wherein the cap portion
includes an interior surface spaced apart from the body portion
interior surface, said body portion interior surface and said cap
portion interior surface defining said vent passage
therebetween.
27. The mask as claimed in claim 26, wherein the cap portion is
detachable from the body portion.
28. The mask as claimed in claim 27, wherein the cap portion and
body portion are rigid and fixed relative to each other when
attached.
29. The mask as claimed in claim 25, wherein the exterior of the
body portion includes grooves or ridges adapted to engage ridges or
grooves respectively on the interior of the cap portion to attach
the cap portion to the body portion.
30. The mask as claimed in claim 25, wherein one of the body
portion or cap portion includes a spacer extending between the
interior surface of the cap portion and the exterior surface of the
body portion.
31. The mask as claimed in claim 25, wherein the vent passage
comprises an inlet portion of relatively large cross-sectional area
adjacent the vent passage inlet and an outlet portion of relatively
small cross-sectional area adjacent the vent passage outlet.
32. The mask as claimed in claim 25, wherein the vent passage
comprises a relatively long inlet portion of constant
cross-section, a relatively long outlet portion of constant
cross-section and a transition portion of smoothly reducing
cross-section extending from the inlet portion to the outlet
portion.
33. The mask as claimed in claim 25, when the vent passage
substantially follows the shape of the exterior of the body
portion.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of Invention
[0002] The present invention relates to a connector for a
respiratory mask and a respiratory mask.
[0003] The invention has been developed primarily for use with a
breathable gas supply apparatus in Continuous Positive Airway
Pressure (CPAP) treatment of, for example, Obstructive Sleep Apnea
(OSA) and other ventilatory assistance treatments, such as Non
Invasive Positive Pressure Ventilation (NIPPV) and will be
described hereinafter with reference to these applications.
However, it will be appreciated that the invention is not limited
to these particular fields of use and also finds application in,
for example, assisted respiration, mechanical ventilation and the
like.
[0004] 2. General Background and Related Art
[0005] CPAP treatment is a common ameliorative treatment for
breathing disorders including OSA. CPAP treatment, as described in
U.S. Pat. No. 4,944,310, provides pressurized air or other
breathable gas to the entrance of a patient's airways at a pressure
elevated above atmospheric pressure, typically in the range 3-20 cm
H.sub.2O.
[0006] It is also known for the level of treatment pressure to vary
during a period of treatment in accordance with patient need, that
form of CPAP being known as automatically adjusting nasal CPAP
treatment, as described in U.S. Pat. No. 5,245,995.
[0007] NIPPV is another form of treatment for breathing disorders
which can involve a relatively higher pressure of gas being
provided in the patient mask during the inspiratory phase of
respiration and a relatively lower pressure or atmospheric pressure
being provided in the patient mask during the expiratory phase of
respiration.
[0008] In other NIPPV modes, the pressure can be made to vary in a
complex manner throughout the respiratory cycle. For example, the
pressure at the mask during inspiration or expiration can be varied
through the period of treatment, as disclosed in the applicant's
international PCT patent application No. PCT/AU97/00631.
[0009] Typically, the ventilatory assistance for CPAP or NIPPV
treatment is delivered to the patient by way of a respiratory,
preferably nasal, mask. Alternatively, a mouth mask or full face
mask can be used. In this specification any reference to a mask is
to be understood as incorporating a reference to a nasal mask,
mouth mask or full face mask, unless otherwise specifically
indicated.
[0010] In this specification any reference to CPAP treatment is to
be understood as embracing all of the above-described forms of
ventilatory treatment or assistance.
[0011] Breathable gas supply apparatus broadly comprise a flow
generator constituted by a continuous source of air or other
breathable gas generally in the form of a blower driven by an
electric motor. The electric motor driving the blower is typically
controlled by a servo-controller under the control of a micro
controller unit. A hospital piped supply can also be used. The gas
supply is connected to a conduit or tube which, in turn, is
connected to the patient's mask which incorporates, or has in close
proximity, a gas washout vent for venting exhaled gases to the
atmosphere. The gas washout vent is sometimes referred to as a
CO.sub.2 washout vent.
[0012] As CPAP and NIPPV treatments are normally administered while
the patient is sleeping, minimization of the noise is desirable for
both the comfort of the patient and any bed partner. The exhausting
of exhaled gas to the atmosphere through the gas washout vent
creates noise due to turbulence generated at a shear layer between
the moving vented gases and the still atmospheric air.
[0013] It is also desirable to locate the vent as close as possible
to the mask in a location which encourages a circulation of flow
within the mask so as to eliminate exhaled CO.sub.2 through the
vent and encourage inhalation of the supplied breathable gas. In
this way, the retention of CO.sub.2 within the mask is minimized.
Further, by increasing the venting efficiency in this manner, the
overall gas outflow is minimized, thereby reducing the opportunity
for noise production.
[0014] One approach to minimize the noise generated by the venting
of the exhaled gas is to direct the gas along an exterior surface
which is a smooth prolongation of an interior surface of the outlet
of the gas washout vent. This reduces the interaction between the
vented gas and the still atmospheric air and, thus, the noise
generated.
[0015] An example of the above approach is the AeroClick vent
produced by MAP which has an annular vent passage that directs the
exhaled gases along an adjacent cylindrical section of equal
exterior diameter to the interior diameter of the annular vent. The
AeroClick vent suffers from several disadvantages. Firstly, the
annular vent is incorporated into a swivel mechanism which requires
a certain amount of play or clearance in order to rotate freely.
This play allows the components forming the interior and exterior
surfaces of the annular vent passage to become misaligned and the
size of the vent outlet being decreased from optimum in some
regions and increased from optimum in other regions. The decreased
area regions increase by the velocity of the gas flowing
therethrough which increases noise and can produce an unpleasant
whistling effect. Secondly, the flow of the gas from the vent
outlet to a state where its velocity is in substantial equilibrium
with the atmosphere is interrupted by an external shoulder closely
downstream of the vent outlet. The shoulder is provided to locate
the gas supply conduit. The stresses in the flow caused by the
shoulder lead to the generation of noise. Additionally, the flow
path from the gas conduit into the vent outlet is not smooth which
introduces discontinuities into the flow which result in further
noise generation.
[0016] Further, the AeroClick vent and other prior art devices that
are of a substantially cylindrical in-line configuration, the
exhaled gas must thus be forced a relatively large distance
(typically around 60 mm) before reaching the outlet to the
atmosphere. This reduces CO.sub.2 washout efficiency, as noted
above, and requires additional patient effort to force the gas
against the direction of flow coming from the flow generator.
[0017] It is an object of the present invention to substantially
overcome or at least ameliorate the prior art disadvantages and, in
particular, to reduce the noise generated by venting exhaled gases
to the atmosphere.
SUMMARY OF THE INVENTION
[0018] Accordingly, in a first aspect, the present invention
provides a connector comprising:
[0019] a mask end for connecting in fluid communication with the
interior of a respiratory mask;
[0020] a supply conduit end disposed at an angle to the mask end
for connecting in fluid communication with the outlet of a
breathable gas supply conduit; and
[0021] a gas washout vent passage having an inlet adjacent to, or
forming part of, the mask end in fluid communication with the
interior of the respiratory mask and an outlet in fluid
communication with the atmosphere, the outlet including an interior
surface that forms a smooth prolongation with an adjacent exterior
surface of the connector, the vent outlet is disposed on the side
of the connector remote the mask end, has a generally part-annular
cross section and is adapted to direct the washout gas in a
direction substantially perpendicular to the longitudinal axis of
the mask end and substantially parallel to the longitudinal axis of
the supply conduit end towards the supply conduit end.
[0022] The supply conduit end is preferably substantially
perpendicular to the mask end. The supply conduit end can also be
angled at approximately 135 degrees to the mask end.
[0023] Preferably, the connector includes a body portion and a cap
portion, said body portion including said interior surface. The cap
portion preferably also includes an interior surface spaced apart
from the body portion interior surface, said body portion interior
surface and said cap portion interior surface defining said vent
passage therebetween.
[0024] The cap portion is desirably detachable from the body
portion. The cap portion and body portion are also desirably rigid
and fixed relative to each other when attached. The exterior of the
body portion preferably includes grooves or ridges adapted to
engage ridges or grooves respectively on the interior of the cap
portion to attach the cap portion to the body portion. One of the
body portion or cap portion preferably also includes a spacer
extending between said cap portion interior surface and said body
portion exterior surface.
[0025] In one form, the vent passage inlet is formed in the body
portion adjacent to and downstream of the mask end, relative to the
washout gas flow, and is in fluid communication with the mask
interior via the body portion.
[0026] In another form, the vent passage inlet comprises part of
the mask end and is in direct fluid communication with the mask
interior.
[0027] The vent passage preferably comprises an inlet portion of
relatively large cross-sectional area adjacent the vent passage
inlet and an outlet portion of relatively small cross-sectional
area adjacent the vent passage outlet.
[0028] The vent passage desirably comprises an inlet portion of
constant cross-section, a relatively long outlet portion of
constant cross-section and a relatively short transition portion of
smoothly reducing cross-section extending from the inlet portion to
the outlet portion. This shape reduces turbulence and affords a
pressure drop from the interior of the mask to the outlet of the
vent passage which reduces the pressure gradient at the outlet of
the vent passage and, thus, reduces the noise generated.
[0029] The vent passage can also include internal ribs and/or an
internal tortuous path to increase the pressure drop, if
required.
[0030] The body portion is preferably of generally part toroidal
shape. The cap portion is preferably of complimentary shape to a
portion of the exterior of the body portion.
[0031] The vent passage preferably curves around the exterior of
the body portion.
[0032] The connector desirably includes a swivel joiner at its
supply conduit end, the exterior of the swivel joiner forming all,
or a part, of said connector exterior surface.
[0033] In one form, the supply conduit end of the connector forms a
smooth prolongation with the supply conduit. The supply conduit end
and the supply conduit desirably have a substantially equal
external diameter.
[0034] In another form, the swivel joiner forms a smooth
prolongation with the supply conduit. The swivel joiner and the
supply conduit having a substantially equal external diameter. The
swivel joiner preferably includes an end of reduced external
diameter adapted to be received within the interior of the supply
conduit.
[0035] In a second aspect, the present invention provides a
respiratory mask comprising:
[0036] a mask shell defining an interior of the respiratory
mask;
[0037] a mask inlet for connecting in fluid communication with the
outlet of a breathable gas supply conduit; and
[0038] a gas washout vent passage having an inlet forming part of
the mask shell and in fluid communication with the interior of the
respiratory mask and an outlet in fluid communication with the
atmosphere, the outlet including an interior surface that forms a
smooth prolongation with an adjacent exterior surface of the mask
shell, the vent outlet is disposed on the side of the mask remote
the mask interior and is adapted to direct the washout gas in a
direction substantially parallel to the longitudinal axis of the
mask inlet and away from the mask inlet.
[0039] Preferably, the mask shell includes a body portion and a cap
portion, said body portion including said interior surface. The cap
portion preferably also includes an interior surface spaced apart
from the body portion interior surface, said body portion interior
surface and said cap portion interior surface defining said vent
passage therebetween.
[0040] The cap portion is desirably detachable from the body
portion. The cap portion and body portion are also desirably rigid
and fixed relative to each other when attached. The exterior of the
body portion preferably includes grooves or ridges adapted to
engage ridges or grooves respectively on the interior of the cap
portion to attach the cap portion to the body portion. One of the
body portion or cap portion preferably also includes a spacer
extending between the interior surface of the cap portion and the
exterior surface of the body portion.
[0041] The vent passage preferably comprises an inlet portion of a
relatively large cross-sectional area adjacent the vent passage
inlet and an outlet portion of a relatively small cross-sectional
area adjacent the vent passage outlet.
[0042] The vent passage desirably comprises a relatively long inlet
portion of constant cross-section, a relatively long outlet portion
of constant cross-section and a transition portion of smoothly
reducing cross-section extending from the inlet portion to the
outlet portion.
[0043] The vent passage preferably substantially follows the shape
of the exterior of the body portion.
BRIEF DESCRIPTION OF THE DRAWINGS
[0044] FIG. 1 is a side view of a first embodiment of a connector
in accordance with the first aspect of the invention, shown
attached to a nasal respiratory mask and forehead support;
[0045] FIG. 2 is a cross-sectional side view of the connector shown
in FIG. 1;
[0046] FIG. 3 is a perspective view of the connector shown in FIG.
1;
[0047] FIG. 4 is a perspective view of the connector shown in FIG.
1 with the cap portion removed;
[0048] FIG. 5 is an underside perspective view of the cap portion
of the connector shown in FIG. 1;
[0049] FIG. 6 is a cross-sectional side view of a second embodiment
of a connector in accordance with the first aspect of the
invention;
[0050] FIG. 7 is a cross-sectional side view of a third embodiment
of the connector in accordance with the first aspect of the
invention;
[0051] FIG. 8 is a cross-sectional side view of a first embodiment
of a respiratory mask in accordance with the second aspect of the
invention; and
[0052] FIG. 9 is a cross-sectional side view of a fourth embodiment
of the connector in accordance with the first aspect of the
invention
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0053] FIGS. 1 to 5 show a first embodiment of the first aspect of
the invention in the form of connector 10. The connector 10 is
shown attached to a nasal respiratory mask 12 and forehead support
device 14. The connector 10 is also suitable for use with a full
face (i.e., nose and mouth) respiratory mask.
[0054] The mask 12 comprises a substantially rigid mask shell 15, a
flexible mask cushion 16 and two slotted lower head strap
connectors 18 (only one connector shown).
[0055] The forehead support device 14 includes a lower portion 20
which is pivotally mounted to an upper portion 22. The upper
portion 22 includes forehead cushions 24 and two slotted upper head
strap connectors 26 (only one cushion/connector shown).
[0056] As best shown in FIG. 2, the connector 10 includes a mask
end 28 for connecting in fluid communication with the interior of
the respiratory mask 12 and a supply conduit end 30 disposed
substantially perpendicularly to the mask end 28 for connecting in
fluid communication with the outlet of a breathable gas supply
conduit 31. The mask end 28 is rotatably coupled to the mask shell
15 by a retaining ring 29. The close proximity of the inlet ports
41, and the vent passage 32 overall, to the interior of the mask 12
advantageously increases CO.sub.2 washout efficiency.
[0057] The connector 10 also includes a gas washout vent passage,
indicated generally by the reference numeral 32, a body portion 34,
a detachable cap portion 36 and a detachable swivel joiner 38. The
conduit 31 is a non-rotatable friction push fit over end 38a of the
swivel joiner 38. The end 38b of the swivel joiner 38 is a
rotatable snap-engage fit with reduced diameter portion 39 of the
body portion 34. The portion 39 is formed from resilient fingers to
allow flexing during snap-engagement with the swivel joiner 38.
[0058] The vent passage 32 includes a pair of inlet ports 41 (see
FIG. 4) formed in the body portion 34 of the connector 10 adjacent
the mask end 28. The inlet ports 41 are in fluid communication with
the interior of the mask 12 via the mask end 28. The vent passage
32 also includes an outlet 40 opening to the atmosphere. The outlet
40 includes an interior surface 42 (comprising an exterior surface
of the body portion 34) that forms a smooth prolongation with an
adjacent exterior surface 44 of the body portion 34. The smooth
prolongation between the interior surface 42 and exterior surface
44 reduces noise by allowing the exhaled gases to vent along a
continuous surface, as previously described. In order to minimize
interruptions or disturbances that could generate turbulence
downstream of the outlet 40, and thus noise, the adjacent exterior
surfaces 46, 48 of the swivel joiner 38 and the gas supply conduit
31 respectively are also formed as smooth prolongations of the
interior surface 42 and adjacent exterior surface 44.
[0059] As best shown in FIG. 3, the vent passage outlet 40 is of
generally part annular cross-section subtending an angle of
approximately 180.degree. and is located on the side of the
connector 10 remote the mask end 28 and, thus, the mask 12. This
ensures that gas is only vented along surfaces displaced, and
facing away, from the mask 12 and the patient, which again
minimizes the risk of the vented gases encountering noise-producing
obstructions.
[0060] Returning to FIG. 2, it can be seen that the vent passage 32
comprises an inlet portion 50 of relatively large cross-sectional
area compared to an outlet portion 52 of relatively small
cross-sectional area. This provides a substantial pressure drop
across the vent passage 32 and reduces the pressure drop between
the outlet 40 and surrounding atmospheric air, again minimizing
noise production. Also, the outlet portion 52 is relatively long in
order to allow the gas to approach a laminar state and, thus,
minimize turbulence before the gas exits to the atmosphere. A
smooth tapering transition portion 54 is disposed between the inlet
portion 50 and the outlet portion 52 which minimizes noise
production by minimizing the introduction of any discontinuities
into the gas flow.
[0061] As best shown in FIGS. 3 and 4, the body portion 34 includes
grooves 56 which are adapted to engage with ridges 58 provided on
the cap portion 36 to allow the cap portion 36 to be manually
attachable/detachable to/from the body portion 34 for ease of
cleaning and replacement. As best shown in FIG. 5, the cap portion
36 also includes an interior strengthening rib 60 to provide
rigidity and ensure the cross-sectional area of the vent passage 32
is not reduced due to external pressure, as may be caused by the
patient rolling over onto their face during sleep. The detachable
cap portion 36 also makes disassembly for cleaning easier and
allows cap portions of various sizes to be used with a single body
portion 34, thereby allowing the size and shape of the vent passage
to be easily and quickly varied for particular treatment
applications.
[0062] Although the connector 10 has been described with reference
to the swivel joiner 38 being interposed between the connector 10
and the breathable gas supply conduit 31, it will be appreciated
that the conduit can be joined directly to the body portion 34 if
the ability to swivel is not required or if a swivel is provided
elsewhere in the gas supply circuit. In that case, it is, of
course, desirable for the external diameter of the gas supply
conduit 31 to be equal to the adjacent external diameter of the
exterior surface of the body portion 34.
[0063] A second embodiment of connector 80 in accordance with the
first aspect of the invention is shown in FIG. 6. Like reference
numerals to those used in describing the first embodiment are used
to indicate like features in the second embodiment.
[0064] The primary difference between the connector 10 and
connector 80 is that the inlet ports 41 are omitted and an inlet
port 82 of the gas washout vent passage 32 is incorporated into the
mask end 28 of the connector 80. Thus providing direct fluid
communication between the interior of the mask 12 and the vent
passage 32 and further minimizing CO.sub.2 retention. The inlet
portion 50 of the vent passage 32 also provides a relatively long
distance over which a gradual reduction in pressure can be
achieved. Further, the interior surface of the vent passage outlet
40 forms a smooth prolongation with the adjacent exterior surface
46 of the swivel joiner 38 rather than the body portion 34, as with
the first embodiment.
[0065] FIG. 7 shows a third embodiment of the connector 90
according to the first aspect of the invention. Like reference
numerals to those used in describing the first embodiment will
again be used to indicate like features in the third embodiment.
The connector 90 also has the vent passage 32 in direct fluid
communication with the interior of the mask 12. However, in this
embodiment, an inlet port 92 is formed in the mask shell 15.
[0066] FIG. 9 shows a fourth embodiment of the connector 130
according to the first aspect of the invention. Like reference
numerals to those used in describing the first embodiment will
again be used to indicate like features in the fourth embodiment.
The connector 130 also has an inlet port 132 formed in the mask
shell 15, similar to the third embodiment. However, in this
embodiment, both the interior surface 42 and the smoothly
prolongating adjacent exterior surface 46 are provided on the
swivel joiner 38. As the gas vents to the atmosphere downstream of
the join 134 between the swivel joiner 38 and the body portion 34,
then any gas leaking through the join 134 cannot disturb the flow
of gas at, or after, the outlet 40. In this way, a further
opportunity for turbulence, and thus noise generation, is
eliminated.
[0067] FIG. 8 shows a first embodiment of a nasal respiratory mask
100 in accordance with the second aspect of the invention. The mask
100 includes a mask shell 102 and a mask cushion 104. The mask
shell 102 includes a mask inlet 106 for connecting in fluid
communication with the outlet of the breathable gas supply conduit
108. The mask 100 includes a gas washout vent passage indicated
generally by the reference numeral 110.
[0068] The mask shell 102 is comprised of a body portion 112 and a
detachable/attachable cap portion 114. The vent passage 110
includes an inlet port 116 formed in the body portion 112 of the
mask shell 102. The inlet port 116 is in direct fluid communication
with the interior of the mask 100. The vent passage 110 also
includes an outlet 118 in fluid communication with the atmosphere.
The outlet 118 includes an interior surface 120 on the exterior of
the body portion 112 that forms a smooth prolongation with an
adjacent surface 122 also provided on the exterior of the body
portion 112. The outlet 118 is adapted to direct the washout gas in
a direction substantially parallel to the longitudinal axis of the
mask inlet 106 and away from the mask inlet 106.
[0069] As with earlier embodiments, the noise produced by venting
the exhaled gas to the atmosphere is minimized by directing the
vented gas on a smooth continuing surface before and after the
outlet 118 and away from the mask 100, the patient and other
potential disturbances. Additionally, as with the earlier connector
embodiments, the cap portion 114 is detachable from the body
portion 112 for cleaning and or replacement with a cap portion of
same, or different, size or shape. The vent passage 110 also
similarly comprises an inlet portion 124 of relatively large
cross-sectional area, a relatively long outlet portion 126 of
relatively small cross-sectional area and a transition portion 128
of smoothly reducing cross-section extending from the inlet portion
124 to the outlet portion 126.
[0070] Although the invention has been described with reference to
the preferred embodiments, it will be appreciated by those skilled
in the art that the invention may be embodied in many other
forms.
* * * * *